Electric motor, generator and commutator system, device and method

ABSTRACT

A direct current (DC) electric motor assembly with a closed type overlap stator winding which is commutated with a timed commutating sequence that is capable of generating a stator rotating magnetic field. The coil overlap of the winding and a timed commutation sequence are such that the current in each slot of the stator is additive and when a previous magnetic pole collapses according to a commutation sequence; the energy released by that previous collapsing magnetic field is captured to strengthen the next magnetic field on the commutation sequence schedule. Electrical currents produced by the collapsing magnetic fields flow to low electric potential and add or subtract to the DC current provided by the commutator thus promoting formation of the next magnetic on commutation schedule. When used with a suitable commutator and rotor, the electric motor assembly provides a true brushless high torque speed controlled Real Direct Current (RDC) motor that operates with higher efficiency and higher power density.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of U.S. patent applicationSer. No. 16/112,707, filed on Aug. 25, 2018; which claims the prioritybenefit of Ser. No. 14/685,599, filed on Apr. 14, 2015; which claims thepriority benefit of U.S. Provisional Patent Application No. 62/014,114,titled “True Brushless DC Motor, Generator and Commutator”, filed onJun. 19, 2014; the entire contents of these applications areincorporated herein by reference.

FIELD OF THE INVENTION

This invention is in the field of electric motors, generators andcommutator systems.

BACKGROUND OF THE INVENTION

The direct current (DC) electric motor was invented in the early 1800's,and the alternating current (AC) electric motors were invented about 50years later in the later 1800's. Since then both types of electricmotors have become highly developed and are used to provide mechanicalforce for a wide variety of different applications.

Brief Review of Basic Electromagnetism and Electric Motor Design

Ampere's Law describes the generation of a magnetic field in thepresence of an electric current. Magnetic fields produced via Ampere'sLaw are used to generate physical magnetic forces in devices such aselectromagnets and electric motors. Faraday's Law of Induction, inaddition to being important for electric motors, also serves as theconceptual foundation for most of the world's electrical generating anddistribution systems. Faraday's Law of Induction describes thegeneration of an electric field from a magnetic field that changes inintensity over time. An electric field produced via Faraday's Law alsogives rise to an electromotive force (EMF) which in turn produces anelectric current. Electric fields produced via Faraday's Law are used togenerate electrical currents in devices such as electric transformersand electric generators.

Motors are generally composed of a stationary part, called the stator,and a moving part, called the rotor. Additional components, such ascommutators, are also often used (particularly with DC motors) tooperate the motor by switching the direction of current between therotor and an external power supply. Rotors typically comprise rotatableshafts and can be constructed in different ways. Different types ofrotors known in the art include permanent magnetic rotors, as well aselectromagnetic coil based rotors including squirrel cage rotors,synchronized rotors, and reluctance based devices including reluctancerotors, stepper rotors, and the like. Although stators with permanentmagnets are known, generally stators are constructed with a stator bodythat incorporates multiple pairs of coils of wire (coils). These statorelectric coils are often, but not always, arranged in a radial manneraround the center of the body of the stator. Rotors often, but notalways, fit inside openings that are often in the center of the statorbody.

In an AC induction motor, such as a three-phase AC electric motor, thetimely alternating sinusoidal current from the AC power supply naturallyswitches the direction of the current flowing through the various motorstator coils, usually many times per second. This creates an alternatingmagnetic field on the stator winding which, when combined with the phaseangle differences between the different phases of the applied ACcurrent, creates a rotating magnetic field on AC motor stator. Ineffect, the sinusoidal variations in the three-phase AC current providea natural self-commutation process. The natural speed of the motor is ineffect set by the frequency of the AC current.

For both AC and DC motors, many applications require that the speed ofthe motor be precisely controlled. Although for some applications,various types of gearing arrangements may be used to regulate speed;often it is important to regulate the underlying speed of the motoritself. This is not entirely always easy. In order to regulate thenatural (e.g., neglecting gearing arrangements) speed of an AC motor,usually the frequency of the AC power supply must be changed. A commonmethod of doing this is to utilize Variable Frequency Drive (VFD)methods. VFD devices create AC current at different frequencies byacting as inverters to transform a DC current from a DC power supplyinto AC current at the desired frequency. However instead of providing asmoothly varying sinusoidal AC current, as might be obtained from a realrotational AC generator, inverters, such as VFD typically uses PauseWidth Modulation (PWM) methods to create pseudo sinusoidal waves. Thejagged, step function type nature of the AC current provided by a VFDcreates Total Harmonic Distortion (THD) effects, and this THD effects inturn create various types of inefficiencies and other problems in ACelectric motors and other devices.

Thus, for example, when a typical VFC driver switches between producing2 KiloHertz (kHz) to 15 kHz AC current, and is used to drive an ACmotor, at the higher frequency, there are typically greater VFD powerswitching losses as well as a greater AC skin effects on the motorwinding. This causes both waste energy and creates unwanted heat. Theseeffects further act to limit the VFC and PWM's maximum switchingfrequency which turn limits how fast the AC motor can rotate.Nonetheless, VFD devices are highly useful because they allow AC motorsto operate with precision speed control. As a result, AC motors areslowly starting to replace the use of traditional DC motors in a widevariety of applications.

For an AC motor, when sinusoidal AC current is used to power the coil,the induced EMF produced by collapsing AC is effectively and naturallysuppressed. However AC motors are often not as strong as DC motors. Thisis because the AC current caused magnetic field is varying continuously,thus preventing the magnetic field in the AC motor's coils from everstaying at their peak for any appreciable amount of time. This limitsthe maximum starting torque that an AC motor can exert.

An additional problem with AC motors is that the varying magnetic fieldcauses induction resistance which, relative to DC motors, furtherrestricts current flow at the maximum supply voltage. This furtherlimits the strength of the AC motor coil's magnetic fields, and thusfurther limits maximum torque, especially at high rotations per minute(RPM). Another problem with AC motors is that AC skin effect (AC tendsto travel along the outside “skin” of a wire, rather than inside thewire) further resists current flow at a high frequency which againlimits its performance. Other problems associated with AC controllers,such as total harmonic distortion (THD), which converts into heat in thestator core, waste energy and reduce the motor's power density for agiven motor frame size.

BRIEF SUMMARY OF THE INVENTION

Aspects of this disclosure include a direct current (DC) electric motorsystem comprising: a stator having a closed type winding including atleast three coils which produce a stator rotating magnetic field whichis coupled with a rotor magnetically, the rotor capable of rotating wheninduced by the stator rotating magnetic field; a commutator coupled tothe stator and which controls the stator rotating magnetic field througha timed commutation sequence; and wherein the stator and the at leastthree coils are configured so that energy released from a collapsingstator rotating magnetic field on a de-energizing commutation step in afirst of the at least three coils is captured by a second of the atleast threes coils energized on a next step of an energizing commutationstep.

Further aspects of the disclosure include an alternating current (AC)induction electric motor system comprising: a stator having a closedtype winding including at least three coils which produce a statorrotating magnetic field which is coupled with a rotor magnetically, therotor capable of rotating when induced by the stator rotating magneticfield; a variable frequency drive coupled to the stator and whichcontrols the stator rotating magnetic field; and wherein the stator andthe at least three coils are configured so that energy released from acollapsing stator rotating magnetic field in a first of the at leastthree coils is captured by a second of the at least three coils.

Further aspects of the disclosure include a method for producing astator rotating magnetic field in a direct current (DC) electric motorsystem comprising: producing the stator rotating magnetic field from aclosed type winding of a stator including at least three coils coupledwith a rotor magnetically, the rotor capable of rotating when induced bythe stator rotating magnetic field; controlling the stator rotatingmagnetic field with a commutator through a timed commutation sequence;and wherein the stator and the at least three coils are configured sothat energy released from a collapsing stator rotating magnetic field ona de-energizing commutation step in a first of the at least three coilsis captured by a second of the at least threes coils energized on a nextstep of an energizing commutation step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a motor assembly 100 as describedherein.

FIG. 1B is an axial view of the motor assembly 100 with commutator 400.

FIG. 1C shows the body of a four slot stator 110 in three-dimensional(3D) perspective, with parallel lengthwise ridges along the internalsurface of the stator.

FIG. 1D shows the front face of the body of the four slot electric motorstator 100 from FIG. 1C above, along with a simple two pole permanentmagnet rotor 120 operating inside of the stator 100.

FIG. 2A shows details of four individual coils for the four slotselectric motor stator 110 of FIG. 1C.

FIG. 2B shows a closed type stator winding diagram of the four slotelectric motor stator 110 from FIG. 1A.

FIGS. 3A-3D show individual coil details for the four slot electricmotor stator 110 previously illustrated in FIG. 2B.

FIGS. 3E-3J show a series of winding diagrams of stator 110 each pairedwith a side view of the stator 110 (pairs FIGS. 3E and 3F; 3G and 3H;and 3I and 3J) to show a current flow direction and stator magnetic fluxdirection at different steps of the commutation sequence.

FIG. 4 shows one embodiment of sixteen steps timed commutation sequencefor the four segment closed type stator winding, each commutation stepadvances 22.5 degree to generate one 360 degree rotation of the magneticfield.

FIGS. 5A-5P illustrates a four segment closed type winding in a seriesof diagrams showing the sixteen step timed commutation sequence of FIG.4 for one full magnetic field rotation.

FIG. 6 shows an alternative commutation switching option that isinterchangeable with the commutation sequence of FIG. 4 and creates thesame field effect.

FIGS. 7A-7H shows the four segment closed type winding commutated withthe eight step timed commutation sequence for one full magnetic fieldrotation.

FIG. 7I shows a segments potential graph of one full magnetic fieldrevolution of an eight step timed commutation sequence.

FIG. 8 shows stator 110 coupled with an embodiment of commutator 400(e.g., a switch commutator) with an electric half bridge switchpresentation.

FIG. 9A is an alternative embodiment of the commutator 400 in the formof a rotary mechanical commutator shown in operation and FIG. 9B showsan exploded view of the rotary mechanical commutator.

FIG. 9C shows an electromechanical diagram of the rotary mechanicalcommutator of FIGS. 9A and 9B.

FIG. 10A shows a winding diagram of stator 110 with conventionalelectric currents flow and magnetic poles produced during a commutationstep on the timed commutation sequence,

FIG. 10B shows a winding diagram of alternative embodiment of FIG. 10Ato illustrate the coil routing.

FIG. 10C shows a front view of the stator 110 illustrating the statormagnetic pole vector (magnetic field pointing direction) in theirgeometric positions in reference to the slot at this timed commutationsequence step.

FIG. 10D is the corresponding settings of the commutator 400 switches.

FIG. 11A shows an example of a three segment closed type stator winding.

FIG. 11B shows an electromechanical diagram of one embodiment of arotary commutator for a twelve step timed commutation sequence.

FIG. 11C shows a twelve step time commutation sequence for the threesegments closed type stator winding,

FIGS. 12A-12L shows the current and stator magnetic field geometricpositions in reference to the stator slot for the twelve steps timecommutation sequence for the three segments closed type stator windingof FIGS. 11A-11C.

FIGS. 13A-13F shows a front view of a three slot stator with currentflow direction and stator magnetic flux direction.

FIGS. 13A-13F show a series of winding diagrams of the three slot statoreach paired with a side view of the three slot stator (pairs FIGS. 13Aand 13B; 13C and 13D; and 13E and 13F) to show a current flow directionand stator magnetic flux direction at different steps of the commutationsequence.

FIG. 14 shows segments potential graph of one full magnetic fieldrevolution of a twelve steps timed commutation sequence for the threeslot stator.

FIG. 15A shows a six step timed commutation sequence for the three slotstator. FIG. 15B shows segments potential graph of one full magneticfield revolution of a six step timed commutation sequence for the threeslot stator.

FIG. 16 shows an embodiment of a twenty step timed commutation sequencefor a five segments closed type stator winding.

FIG. 17 shows a wiring diagram for a three segments four pole closedtype stator winding where P=3, N=1, R=2, and S=6.

FIG. 18 shows a three segments six pole closed type stator winding whereP=3, N=4, R=3, and S=36.

FIG. 19 shows a three segments sixteen pole closed type stator windingwhere P=3, N=2, R=8, and S=48.

FIG. 20 shows a four segments two pole closed type stator winding whereP=4, N=2, R=1, and S=8.

FIG. 21 shows a four segments six pole closed type stator winding whereP=4, N=3, R=3, and S=36.

FIG. 22 shows a five segments two pole closed type stator winding whereP=5, N=1, R=1, and S=5.

FIG. 23 shows a six segments two pole closed type stator winding whereP=6, N=1, R=1, and S=6.

FIGS. 24A-24B show a six segments two pole closed type stator windingwhere P=6, N=2, R=1, and S=12. FIG. 24A shows one de-energize step andFIG. 24B shows one energize step.

FIG. 25 shows an eight segments two pole closed type stator windingwhere P=8, N=1, R=1, and S=8.

FIG. 26 shows a ten segments two pole closed type stator winding whereP=10, N=1, R=1, and S=10.

FIG. 27 shows a twelve segments two pole closed type stator windingP=12, N=1, R=1, and S=12.

FIG. 28A shows a three phase AC current with artificially predeterminedtwelve step segments potential points to match the timed commutationsequence shown in FIG. 28B.

FIG. 29 is a perspective view of an AC motor assembly2900.

DETAILED DESCRIPTION

In contrast to AC motors, DC electrical motors don't have a “naturalcommutator”. To operate a DC electrical motor, the DC current passingthrough the various coils of the DC motor must be varied using varioustypes of commutator devices. In some DC electric motor designs, thestator may incorporate either permanent magnets or non-switchedelectromagnets (e.g., non switched stator coils), and instead themagnetic field of the rotor may be varied by a function of time, usuallyby switching the direction of current flowing through the windings ofthe various rotor coils.

In some alternative DC motor designs, a rotating magnetic field isgenerated on the DC electric stator instead. In these designs, the motorstator generally comprises various coils (each coil usually formed frommultiple wire windings). The motor stator can be operated bysequentially switching or commutating the direction of the currentflowing through the windings of the various motor stator coils in amanner that produces a rotating magnetic field. This rotating magneticfield in turn can be used to induce rotation in a rotor with suitablemagnetization or reluctance.

In some types of DC motors, such as step motors and reluctance motors,the coil windings are electrically driven by individual electric halfbridges (allow connected terminal connect to either positive or negativeof DC power supply). When a particular coil winding is powered withelectrical current, it creates a magnetic field, and in essence there isenergy stored in this magnetic field.

More specifically, applying electric current through a conductor coil(e.g., a coil of conducting wire) creates a magnetic field. Energy isstored in this magnetic field, in a manner not unlike storing kineticenergy in a rotating flywheel. When this applied electrical current isremoved, an EMF (electromagnetic force) is induced, and this storedmagnetic field energy is discharged in the form of an electric currentat a voltage (electrical potential). According to Lenz's law, an inducedelectromotive force (EMF) always gives rise to a current whose magneticfield opposes the original change in magnetic flux. Thus the dischargedelectrical current flows in the same direction as the original appliedcurrent.

The problem with such types of DC motors is that during the commutationprocess, once power is removed from a previously powered coil, thatcoil's magnetic field promptly collapses. The energy stored in the coilscollapsing magnetic field (e.g., self-induced EMF) previously stored inthe coil winding, is now released. Where does it go? For AC motors, theAC sinusoidal current acts to suppress this self-induced EMF naturally.However for DC motors, the energy in the coil winding's self-induced EMFcomes back as self-induced EMF electrical current and this has to gosomewhere. With present designs, the self-induced EMF electrical currentgenerally travels back to the DC power supply or is consumed intoballast resistors. This is not a problem for small DC motors, but forhigh power motors, the magnitude of the self-induced EMF electricalcurrent is quite high, and it can become very challenging to handle.This is a major reason why prior art step motors can only handle lowamounts of power (e.g., up to few hundred watts); and even prior art DCreluctance motors can only handle a few kilowatts of power.

At the same time DC motors, in particular DC brushed motors, have somecompelling advantages for some applications. For example, DC brushedmotors can be designed with a stationary field coil and commutatedarmature coil winding scheme. Rush starting a DC current can create verylarge amounts of starting torque. As a result, such DC motor designs areoften favored in various types of high starting torque applications,such as for traction motors on railways, city trolleys and subway thirdrail systems.

One problem with DC brushed motors, however, is due to the brushesthemselves. The brushes create friction, contact resistance heat loss,plus armature winding resistance loss. These effects create large amountof heat trapped in the relatively small rotor part of the motor, it isdifficult to remove this armature heat, as a result, brushed DC motorsare typically built on an open frame design to allow excess heat toescape or force vented. As the brushes used to provide current to thearmature usually wear quickly, the DC brushed motors of large size areoften high maintenance devices, and their armatures/rotors have to befrequently removed and reworked for maintenance.

In the detailed description of the embodiments disclosed herein, therewill be described an improved electric motor, which can be driven bymultiphase AC current or commutated by DC current. Because AC isnaturally commutating as its name stands for, it does not require acommutator and a sinusoidal AC naturally suppresses self-induced EMF.Electric motor DC commutation is explained in detail in this disclosure.In at least one embodiment, the improved electric motor will generallycomprise at least one stator and commutation system for DC operation.However alternate embodiments are also contemplated accordingly (e.g.,universal motors with multiple stators and even possibly multiplerotors). The embodiments disclosed herein will typically operate usingelectrical current (power, energy) from at least one DC power source(i.e., DC power supply, DC energy source, DC current source). Morespecifically, there is disclosed herein a direct current (DC) electricmotor assembly with a closed type overlap stator winding which iscommutated with a timed commutating sequence that is capable ofgenerating a stator rotating magnetic field. The coil overlap of thewinding and a timed commutation sequence is such that the current ineach slot of the stator is additive and when part of a previous magneticpole collapses according to a commutation sequence; the energy releasedby that part of a previous collapsing magnetic field is captured tostrengthen the next magnetic field on the commutation sequence schedule.Electrical currents produced by the collapsing magnetic fields flow tolow electric potential and add or subtract to the DC current provided bythe commutator thus promoting formation of the next magnetic field oncommutation schedule. When used with a suitable commutator and rotor,the electric motor assembly provides a true brushless high torque speedcontrolled DC motor that operates with higher efficiency and higherpower density.

FIG. 1A is a perspective view of a Real Direct Current (RDC) motorassembly 100 as will be described in detail. Besides stator 110, themotor assembly features rotor 120 and coil windings 112 connected tocommutator 400 (e.g., a switch commutator). The simple permanent magnetrotor 120, with a North and South Pole, can rotate inside the stator 110in response to stator rotating magnetic fields created by the coilwindings 112. Coil windings 112 are classified into two different typesin this disclosure: i) closed type winding or ii) open type winding. Ina closed type winding, a closed path is formed around the stator. Thestarting point of the winding is reached again after passing throughpart or all the turns. Commutator segments (described below) areconnected to various winding coils 112 and as a result the current inthe coil windings gets divided into different parallel paths. Thecurrent flowing through the coil windings changes continuously. Incontrast, in open type windings such as star connected AC machines, acommutator is not used. In such cases the ends of each section of thewinding can be brought at terminals to do the required type ofinterconnection externally. The open type of winding is often preferredover closed type as it gives better flexibility in design and freedom ofconnections. In this disclosure to allow the stator closed type windingto be clearer and more easily appreciated, rotors (e.g., 120) are notnecessarily shown in the other figures of this description. However, allstators described herein should be assumed to be associated with anappropriate rotor(s) to form an electric motor assembly. Also, althoughonly a four slot stator and closed type winding is shown in detail inFIGS. 1A-1D for use in motor assembly 100 it is to be understand thatthe number of slots in alternative embodiments of the stator can rangefrom a minimum of three to one hundred and even greater than one hundredin number since there are actually no set, fixed upper limits on thenumber of slots in a stator. It should be noted that the recitation ofranges of values in this disclosure are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. Therefore, any given numerical range shallinclude whole and fractions of numbers within the range. For example,the range “1 to 10” shall be interpreted to specifically include wholenumbers between 1 and 10 (e.g., 1, 2, 3, . . . 9) and non-whole numbers(e.g., 1.1, 1.2, . . . 1.9). Therefore, for example, when describingoperation of a 4 slot stator, the description would apply equally to a3, 8, 16, 72 or 100 plus slot stator (for example) and those differentnumbered slotted stators should be considered to be implementedaccording to the methods and systems described herein and are part ofthis disclosure.

When electric motors were originally developed in the 1800's, theavailable mechanisms to control the operation of electric motors werelimited to relatively crude mechanical devices which had less thanperfect timing and flexibility. Due to rapid advancing of modern solidstate electronic technology, the performance of electric motors such asmotor assembly 100 can be considerably improved. Because the coils inthis closed type stator winding are interconnected, as described abovethe “closed type” means that from any point of the winding, it can betraced back to the same point along the coils. Because electric currentflows naturally from high to low potential through least resistance, andthe interconnected coils offer the least resistance path, it isregardless whether this current comes from external power orself-induced current from collapsing magnetic field on the coils.Therefore, closed type windings enable DC current switching on the coilswithout the penalty of self-induced high potential/voltage build up onthe closed type stator winding. Also, when the closed winding isproperly commutated, the self-induced current is facilitated to advancethe stator rotating magnetic field and/or strengthen the next magneticfield on timed commutation sequence. The energy from collapsing field istherefore effectively captured inside the winding with the embodimentsdescribed herein.

FIG. 1B is an axial view of motor assembly 100 with commutator 400located on the exterior of the assembly. Compared with traditionalbrushed DC motor, the maintenance problems of brushes inside the motor'sbody can be avoided by instead using an external type commutator systemas shown in FIG. 1B. (However, in alternative embodiments, thecommutator may be located inside the motor assembly 100). The commutator400 is typically integrated electronics similar to AC motor VFD driver,made up of microprocessor, sensors, switches, input/output interface,and software to control the commutation of the motor assembly 100. Thetimed commutation sequence may be generated by coupling the rotorposition mechanically or electronically with built in position sensorsinside motor assembly 100 as a closed loop feedback such that when afirst commutation step is commanded and the rotor 120 is induced to adetected position, a second commutation step is commanded so that therotor 120 is induced to next position. On and on, so that the closedtype stator winding DC motor is self-commutating. The position sensorscan be any magnetic sensor, optical sensor, or solid state switch.

FIG. 1C shows a three-dimensional perspective view of the body of a fourslot (or segment) stator 110 with parallel lengthwise ridges along theinternal surface of the stator. The spaces between the ridges are the“slots” (e.g., S1-S4) and the coils are formed from conductor wires thatare wound inside each slot around the ridges so that the coils passthrough the slot. The cylinder (stator body 110) is generally made ofmagnetically permeable material and the ridges thus form the center ofcores that concentrate and shape the magnetic fields created by currentflowing through the coil windings 112.

FIG. 1D shows the front face of the body of the four slot electric motorstator 110 from FIG. 1C above, along with a simple two pole permanentmagnet rotor 120 placed inside of the stator for illustration purposes.As previously stated, each of the motors disclosed herein should beassumed to have a rotor whether shown or not.

As will be discussed, the methods and systems described herein may beused to produce and operate a universal electric motor 100 comprising atleast one rotor 120, one stator 110 and a commutator 400. The stator 110will generally comprise a plurality of stator winding coils 112 that areheld in a defined geometric position with respect to each other. Thesestator winding coils 112 are configured to be energized and deenergizedwith DC electrical energy by commutator 400 (e.g., a switch commutator).The stator coil and timed commutation sequence will generally beconstructed to produce additive current in the stator slots (S1 to S4)to create a magnetic field. The magnetic field will produce a pluralityof time varying and geometrically separated stator magnetic poles thatin turn produce a DC created stator rotating magnetic field. The timedcommutation sequence and the closed type winding schemes should be suchthat when self-induced EMF occurs from an electrically energized todeenergized coil or coils, it produces a current from the collapsingmagnetic field. The self-induced EMF current should advance the statormagnetic field and help build the next magnetic field on the timedcommutation schedule. The timed commutation sequence can be generatedwith a logic circuit(s) or micro processor(s) for open loop control, itcan also be generated by detecting the rotor position with built inHall-effect or magnetic sensors inside motor assembly 100 as a closedloop feedback such that when first commutation step is commanded and therotor 120 is induced to a detected position, a second commutation stepis commanded so that the rotor 120 is induced to next position. On andon, it can be phrased as self-commutation.

The system and method disclosed herein may produce improved DC electricmotors that are efficient and potentially more durable than prior art DCelectrical motors of this type. In addition to lower efficiency, priorart motors also tend to impose additional stress on various types ofelectronic circuitry. The embodiments disclosed herein can also help toachieve precision control over the speed of the DC motor.

The rotor 120 shown in FIG. 1D can be configured to produce rotormagnetic poles inside electric motor 100. This rotor 120 will generallybe geometrically constrained proximate to the stator 110 (usually byvarious mechanical fixtures) in a manner that allows the rotor magneticfield to interact with a stator magnetic field produced by the closedtype stator winding 112 and also allow the rotor to rotate about a rotoraxis of rotation. As will be discussed herein, a stator created rotatingmagnetic field induces rotation in the rotor 120. The rotor 120 may beof various types including a squirrel cage induction rotor, woundedrotor, permanent magnet rotor, or reluctance rotor. In at least oneembodiment, the rotor 120 and its corresponding magnetic poles may beshaped to match the configuration of the stator ridges, as well as tomaximize the torque produced as the result of the stator's rotatingmagnetic field produced by the closed type stator winding 112. Note thatin many constructions although the rotor may often be placed inside thestator, however, this need not always be the case. In alternativeembodiments, the motor 100 may be designed with substantial portions ofthe rotor or even the entire rotor, held outside of the stator. Therotor and stator can also be configured in a horizontal flux motordesign in which the rotor and stator are held in a face to faceconfiguration.

Although the stator 110 is a brushless stator as described so far, inalternative embodiments the commutator used to provide power to thestator closed type winding need not be brushless. So long as the closedtype stator winding can receive DC electrical energy, according to atimed commutation sequence, from a DC electrical power source by using acommutator system that commutator system may include mechanicalswitches, rotary switches, mechanical relays, solid state switches,logical devices, H-bridges, and/or computer processors (e.g.,microprocessors, microcontrollers, other logical devices, and the like).

Various types of coil winding 112 schemes can be used as well. Theseschemes include brushed DC motor armature winding methods such as any ofa group consisting of: lap winding, wave winding, and Gramme-ringwinding methods.

FIG. 2A illustrates details of four individual coils 112 for the fourslots S1-S4 electric motor stator 110 of FIG. 1C. FIG. 2B shows a closedtype stator winding diagram of the four slot electric motor stator 110from FIG. 1A. FIG. 2B is diagrammed according to the convention in whichthe stator body 110 is shown in flat format as if the stator 110 is cutlengthwise in between one of its slot of the stator cylinder thenunrolled to a flat state. Commutation segments are shown with segmentsmarked as X* squares (e.g., 1*, 2*, 3*, and 4*).

FIGS. 3A-3D show individual coil winding details (Coil #1, Coil #2, Coil#3, and Coil #4) for the four slots electric motor stator 110 previouslyillustrated in FIGS. 1A-2B. It should be noted how the coil bypassesslots. In FIG. 3A, the starting end of the Coil #1 (designated as 1 s atcommutation segment 1*) goes into stator Slot 1 (S1), marked as 1 f,bypasses Slot 2 (S2), and is returned on stator Slot 3 (S3) (designatedas 1 b). The tail end of Coil #1 (designated as 1 t) is then connectedto the start end of next successive Coil #2 and connected to commutationsegment or phase 2*. (This convention will be used throughout thisdisclosure). In FIG. 3B, the starting end of Coil #2 (designated as 2 s)goes into stator Slot 2, marked as 2 f, bypasses Slot 3, and is returnedon stator Slot 4 (marked as 2 b). The tail end of Coil #2 (designated as2 t) is then connected to the start end of next successive coil #3 andconnected to commutation segment or phase 3*. In FIG. 3C, the startingend of the Coil #3 (designated as 3 s) goes into stator Slot 3, markedas 3 f, bypasses Slot 4, and is returned on stator Slot 1 (designated as3 b). The tail end of Coil #3 (designated as 3 t) is then connected tothe start end of next successive Coil #4 and connected to commutationsegment or phase 4*. In FIG. 3D, the starting end of the Coil #4(designated as 4 s) goes into stator Slot 4 (marked as 4 f) bypassesSlot 1 and is returned on stator Slot 2 (designated as 4 b). The tailend of the Coil #4 (designated as 4 t) is then connected to the startend of next successive Coil #1 and connected to commutation segment orphase 1*. Here each (front side) coil occupies one slot and thisconvention will be used throughout the various figures of thisdisclosure. Generally “commutation segment”, “segment” and “phase”alternative terminologies will also be used herein.

FIGS. 3E-3J show a series of winding diagrams of stator 110 each pairedwith a side view of the stator 110 (pairs FIGS. 3E and 3F; 3G and 3H;and 3I and 3J) to show a current flow direction and stator magnetic fluxdirection at different steps of the commutation sequence. In FIGS. 3E,3H and 3J, the coils are shown in two turns for easy of illustrating theend winding (outside of slot coil winding) current direction. A coil inthe back is shown in dashed line and in the front in solid line. A plussign in a circle shows current going into the slot and a dot in thecircle shows current flow out of slot. FIGS. 3E and 3F show Coil #1being energized together with Coil #2, Coil #3 and Coil #4 and in themoment Coil #1 trail end is commutated to high potential segment *2.Between FIGS. 3E and 3G, the Coil #1 energized magnetic field startscollapsing; current generated from the collapsing field continues toflow to low potential segment 3* through coil #2 which strengthens theCoil #2 generated magnetic field. The result of the energy from thecollapsing field is redirected to build or strengthen a coming magneticfield in the commutation schedule and energy is captured inside theclosed type stator winding. Also at the same moment, the Coil #3 trailend is commutated to low potential segment 4*. From FIGS. 3E to 3G, theCoil #3 energized magnetic field starts collapsing; current generatedfrom the collapsing field continues to flow to low potential segment 4*through Coil #4 which strengthens the Coil #4 generated magnetic field.Again the result of the energy from the collapsing field is redirectedto build or strengthen a coming magnetic field in the commutationschedule and energy is captured inside the closed type stator winding.The stator magnetic field is effectively advanced approximately 45degrees on this de-energize commutation step. From FIG. 3G to 3I, whenthe Coil #1 start end is released from high potential segment 1*, Coil#1 is getting charged with electric energy as current which effectivelyadvances the stator magnetic field. At substantially the same momentwhen the Coil #3 start end is released from low potential segment 3*,Coil #3 is getting charged with electric energy as current whicheffectively advances the stator magnetic field. The stator magneticfield is advanced approximately 45 degrees on this energize commutationstep. In the traditional AC motor lap or concentric winding, the currentin the end coil portion of the coil (i.e., the outside of the slotportion) does not contribute to generate the stator magnetic field. Allthe coils in this closed type winding include coil portions outside ofslots substantially equally contributing to energize the stator magneticfield, in other words the end coil portion and the in slot coil portionare all integrally part of the coil winding.

FIG. 4 shows an alternative sixteen step timed commutation sequence forthe four segment closed type stator winding 112 described in FIGS.1A-3J, each commutation step advances approximately 22.5 degrees togenerate one 360 degree rotation of a magnetic field. FIGS. 5A-5P showthe four segment closed type windings 112 commutated with a sixteen steptimed commutation sequence for one full magnetic field rotation. Currentand direction in the windings 112 of FIGS. 5A-5P are shown by up anddown arrows. Note that with each step of commutation, the magnetic fieldis advanced from the previous 22.5 degree step to create acounterclockwise rotating magnetic field. The reversed timed commutationsequence reverses the stator magnetic field direction of advancing,consequently reversing the rotor rotation. FIGS. 5A-5P best interpretthis. Moving from FIG. 5A to FIG. 5B to FIG. 5C, it should be noted howcurrent regenerated from the discharging magnetic field of FIG. 5B froma just deenergized Coil #1 is redirected to the next charging magneticfield of step #3 (FIG. 5C) because the electric current flows from highelectric potential to low electric potential. At the instance of FIG.5C, segment 2* is connected to positive DC power source; Coil #1 at bothends is placed at substantially the same high potential; the magneticfield generated by Coil #1 is starting to collapse; Coil #1 currentcreated by the collapsing magnetic field will continue to flow into lowpotential on the closed type winding, which is segment 3*; and Coil #2is offering the route for said current until the field is completelycollapsed. The net effect of the discharging current from Coil #1generated from the collapsing magnetic field have effectively advancedmagnetic field approximately 22.5 degrees in this timed commutationsequence step and the discharging current is advancing and helping buildnext on the coming magnetic field on the timed commutation schedule.There is no high voltage generated on this closed coil winding inducedby collapsing magnetic field. FIGS. 5A-5P are also interpret thecharging and discharging step. There is a charging step when at leastone more coil is energized on the closed type winding to advance thestator magnetic field and a discharging step when at least one morecoil's both end is commutated to the same electric potential and thecoil or coils would discharge the magnetic field energy stored fromprevious charging step. The discharging of the field induces current tocontinue to flow in a previous current direction until the dischargingmagnetic field is completely collapsed. The induced current togetherwith current from the DC power supply results in advancing the rotatingmagnetic field one commutation step. The timed commutation sequencecontinuously commutating the closed type winding and advance themagnetic field forward, the advance magnetic field forward creates a DCgenerated stator rotating magnetic field and the rotating magnetic fieldrotates on the pace and direction of the timed commutation sequence. Thetimed commutation sequence on the closed type winding enables DCcommutation without the penalty of inducing high electric potential onthe closed type winding and this closed type winding can handle large DCelectric current (e.g., over hundreds of amperes).

FIG. 6 is an example of one of the alternative commutation switchingoptions that are interchangeable and may be used to create the samefield effect of FIG. 4 in the motor assembly 100 illustrated in FIGS.1A-3D. The eight commutation steps shown in FIG. 5B, FIG. 5D, FIG. 5F,FIG. 5H, FIG. 5J, FIG. 5L, FIG. 5N, and FIG. 5P can also be combined tocreate an eight step timed commutation sequence with each commutationstep advancing substantially 45 degrees of the magnetic field as shownin FIGS. 7A-7H. FIG. 7I shows a segments potential graph of one fullmagnetic field revolution of an eight step timed commutation sequence.The basic operation principle behind the four slot closed type statorwinding 112 and corresponding timed commutation sequence shown above canapply to any segment count of closed type winding and correspondingtimed commutation sequence described herein. The closed type statorwinding 112 and timed commutation sequence should be configured so thatself-induced current from a collapsing magnetic field contributes toadvance the stator rotating magnetic field and facilitate current in theslot additive to create the magnetic pole. Current cancelation in thesame slot should be avoided unless to advance the stator magnetic field.For the closed type winding to consist of more than four segments, thereare many more options with how many more slots a coil can pass over andhow the commutator can be placed on the segments. The general method andsystem described herein still applies and additionally, balancedmagnetic pole placement and paced commutation is preferred wheneverpossible.

The total slot count of the closed type stator winding can be describedwith the stator winding formula: S=P×N×R where S is total slot count onthe stator; P is at least three Segments/Phases; N is at least one sloteach coil occupies; and R is at least one for stator pole pair count onthe stator (e.g., R=2 for a four pole winding). Basically unlimitedmotor stator poles and slots combinations can be configured with thisformula (or methodology) and are included in this disclosure herein.Similar like a Brushless DC (BLDC) motor, R time's winding magneticfield revolution makes one rotor revolution.

FIG. 8 shows an embodiment of commutator 400 (e.g., switch commutator)which may be used in connection with FIGS. 1A-7I discussed above in anelectric half bridge switch presentation. The electric half bridge isconnected (through wire 801) to the closed type stator winding 112through commutation segment 1* to facilitate the timed commutationsequence. Note the other commutation segments are also connected to thecorresponding half bridge via other wires (802, 803, and 804). In orderto keep the drawings simple, generally these half bridges and connectingwires between the electric half bridge and the commutation segment arenot shown. Thus each of the commutation segments (with segments markedas X* squares) are connected to their corresponding half bridge (X′circles), which in turn connect to a DC positive power supply (notshown) through a high switch and is also connected to the DC groundthrough a lower switch.

FIG. 9A is an alternative embodiment of a commutator 900 which may beused with the embodiments of FIGS. 1A-7I. FIG. 9A illustrates a rotarymechanical commutator 900 in operation and FIG. 9B is an exploded view.The stationary spring loaded commutation segment brushes 1*, 2*, 3*, and4* shown in FIG. 9B are sequentially mounted around the rotatingelectric poles 902 and 904. The rotary electric pole assembly 906 can bemechanically coupled to the motor rotor 120 for self-commutation or bedriven by a second commutation motor governed by a timed commutationsequence. DC power is delivered to the rotating electric pole assembly906 through slip rings 908 and 910 which are electrically interconnectedwith the electric poles 902 and 904 through wires 912 and 914, and theslip rings 908 and 910 are electrically in contact with spring loadedpole brushes 916 and 918 which are in turn electrically connected withstationary power supply. FIG. 9C shows an electromechanical side viewdiagram of FIGS. 9A and 9B highlighting the stator magnetic fieldvector. The commutation segments are sequentially and equally spacedaround the rotary electric poles. The electric pole and the segmentangular space (time angle) is three fourths of the angular space (timeangle) of the segment pitch such that each of the eight commutationsteps will have the same time interval or a paced commutation. Howeverthe segment and electric pole time angle can vary which will create alimitless un-paced commutation sequence. In FIG. 9C, slot numbers S1-S4are in between the segments. A paced commutation is used in the sensethat each timed commutation sequence step has a substantially equalinterval, or accelerated pace, or decelerated pace as its name standfor.

FIG. 10A shows electric current flows and magnetic poles produced duringa commutation step on the timed commutation sequence. The Magnetic NorthPole is drawn on an upward current slot and Magnetic South Pole is drawnon a downward current slot. The timed commutation sequence is presentas: a plus symbol in a box attached to segments 1* and 2* representscommutator switch 1 h and 2 h is closed and connected to DC powerpositive; a negative symbol in a box attached to segments 3* and 4*represents commutator switch 3 l; and 4 l is closed and connected to DCpower negative. (This convention is used throughout this disclosure).FIG. 10A also uses a number to represent stator slot number (i.e., Slot1 is simplified as S1; Slot 2 is simplified as S2; Slot 3 simplified asS3; and Slot 4 simplified as S4). FIG. 10B shows an alternative way ofinterconnected coil routing to that of FIG. 10A with an independent coilwinding for each pair of poles. FIG. 10C shows a front view of thestator 110 illustrating the stator magnetic pole vector (magnetic fieldpointing direction), in their geometric positions reference to the slotat this timed commutation sequence step. FIG. 10D is the correspondingsettings of the commutator 400 switches.

FIG. 11A illustrates an alternative embodiment of a three segment closedtype stator winding 1100. FIG. 11B shows an electromechanical diagram ofone embodiment of a rotary commutator 1110. FIG. 11C shows a twelve steptime commutation sequence for the three segments closed type statorwinding 1100. FIGS. 12A-12L show the current and stator magnetic fieldgeometric positions with reference to the stator slot for the twelvesteps time commutation sequence for the three segments closed typestator winding 1100. Each commutation step advances approximately 30degrees of magnetic field. Note all the even steps have currentcancelation in one slot which is undesirable. This even stepped intervalshould ideally be kept as short as possible in the twelve step timedcommutation sequence or simply removed and instead electric half bridgedead time control to facilitate the charging step should be used. Thedead time control is at no time both the high and low switch of the halfbridges which would turn on the same time to avoid current shoot through(or “short the power supply”). The “dead time control” is performed bysoftware or hardware. The physical time it takes to perform dead timecontrol provides enough time for the coils get charged to advance themagnetic pole.

FIGS. 13A-F show a front view of three slot stator 110 with current flowdirection and stator magnetic flux direction. In corresponding FIGS. 13Aand 13B, the coils are drawn in two turns for easy of showing the endwinding (outside of slot coil winding) current direction. A coil in theback is drawn in dashed line and drawn in solid line in the front. Aplus sign in a circle shows current going into the slot and a dot in thecircle shows current flow out of slot. FIG. 13A shows Coil #1 gettingcharged together with Coil #2 and Coil #3. At this moment Coil #1 trailend is commutated to high potential segment *2. In FIGS. 13C and 13D,the Coil #1 charged magnetic field starts collapsing; current generatedfrom the collapsing field continues to flow to low potential segment 3*through Coil #2 which strengthens the Coil #2 generated magnetic field;the result of the energy from the collapsing field is redirected tobuild or strengthen an coming magnetic field in commutation schedule andenergy is captured inside the closed type stator winding. The statormagnetic field is effectively advanced approximately 30 degrees on thiscommutation step. In FIGS. 13E and 13F, when the Coil #1 start end isreleased from high potential segment 1*, Coil #1 is getting charged withelectric energy as current which effectively advance the stator magneticfield. Notice that the current in the end coil (outside of the slot)substantially equally contributes to energize the stator magnetic fieldand is an integral part of the coil winding to generate the statormagnetic field. As a result, this closed type stator winding results inmore stator power density. This characteristic of current flow isespecially beneficial for a very short slot motor stator.

FIG. 14 shows a segments potential graph of one full magnetic fieldrevolution of a twelve step timed commutation sequence for the threeslot stator 1100.

FIG. 15A shows an alternative six step timed commutation sequence forthe three slot stator 1100 version of DC motor assembly 100. FIG. 15Bshows segments potential graph of one full magnetic field revolution ofthe six step timed commutation sequence. For such six step pseudo pacedtimed commutation sequence, the stator magnetic field is advancedapproximately sixty degrees from the previous step with each step ofcommutation. Again there are unlimited combinations of timed commutationsequences with varying step intervals, however, only one twelve steppaced timed commutation sequence and one pseudo-paced six steps timedcommutation sequence.

FIG. 16 shows an embodiment of a twenty step timed commutation sequencefor a five segments closed type stator winding version of DC motorassembly 100. Again all the even steps have current cancelation in oneslot which is vary undesirable and this even stepped interval shouldkept as short as possible in the twenty step timed commutation sequence.

FIG. 17 shows a three segments four pole closed type stator windingwhere P=3, N=1, R=2, and S=6. Each coil occupies two slots one pairpoles apart.

FIG. 18 shows three segments six pole closed type stator winding whereP=3, N=4, R=3, and S=36. Each coil occupies four adjacent slots; thewinding is spilt into three same groups.

FIG. 19 shows three segments sixteen pole closed type stator windingwhere P=3, N=2, R=8, and S=48. Each coil occupies two adjacent slots;the winding is spilt into eight same groups.

FIG. 20 shows four segments two pole closed type stator winding whereP=4, N=2, R=1, and S=8. Each coil occupies two adjacent slots.

FIG. 21 shows four segments six pole closed type stator winding whereP=4, N=3, R=3, and S=36. Each coil occupies three adjacent slots; thewinding is spilt into three equal groups.

FIG. 22 shows five segments two pole closed type stator winding whereP=5, N=1, R=1, and S=5.

FIG. 23 shows six segments two pole closed type stator winding whereP=6, N=1, R=1, and S=6.

FIGS. 24A and 24B show six segments two pole closed type stator windingwhere P=6, N=2, R=1, and S=12. FIG. 24A shows one de-energize step andFIG. 24B shows one energize step

FIG. 25 shows eight segments two pole closed type stator winding whereP=8, N=1, R=1, and S=8.

FIG. 26 shows ten segments two pole closed type stator winding whereP=10, N=1, R=1, and S=10.

FIG. 27 shows twelve segments two pole closed type stator winding P=12,N=1, R=1, and S=12.

A method of constructing a first specific example is described inrelation to the winding scheme of FIG. 19. A motor stator wasconstructed by taking apart and rewinding from the beginning an electricsedan traction motor produced by CODA Automotive™ of Los Angeles, Calif.This motor was a QUM™ brand OEM three phase AC motor having a 48 slotstator. It was constructed with three phase lap winding using 52 strandAWG 22 magnet wires for each phase. The rotor for this motor was a 16pole permanent magnetic type rotor. This motor stator was thenre-constructed and re-winded according to the methodology of P=3, N=2,R=8, S=P×N×R=48. The eight three segment coil winding was connected inparallel, each of the three coils in the winding, according to theembodiments described herein, using 36 turns, 2 strand AWG #19 magnetwires and occupies two slots. The commutator used for this reconstructedmotor utilized original analog portion of the VFD driver equipped withthe sedan, and reprogramed the Arduino Mega microprocessor, with theFIG. 11C commutation sequence.

A method of constructing a second specific example is described asfollows. A McLean Engineering™ model K33HXBLS-673 AC induction motor wastaken apart and rewound per FIG. 20, to form a four pole squirrel cagetype DC induction motor. Here the methodology used was: P=4, N=2, R=2,S=P×N× R=16. The closed type stator winding was internally parallelconnected. Each of the eight windings was wound using 10 turns of AWG22magnet wire. One Atmel™ 328 MCU (ATmega328 8-bit AVR RISC-basedmicrocontroller) was used to drive four electric half bridges togenerate the timed commutation sequence FIG. 4A. The half bridgecommutated 24 VDC power from the DC power supply to the motor windingsto create four rotating magnetic poles on the stator.

A method of constructing a third specific example is described asfollows. An Oriental Motor USA™ model E0144-344 AC induction motor wastaken apart and reconstructed and rewound from the beginning to form afour pole squirrel cage type DC induction motor. The stator wasconstructed as 12 segment closed type winding FIG. 27. This winding wasinternally parallel connected and each segment was connected to one pairof mechanical relays. Here the rotor was a squirrel cage type rotordesign. Each of the 24 windings was wound using 16 turns of AWG21 magnetwire. The commutator also used was one Atmel™ 328 MCU (ATmega328 8-bitAVR RISC-based microcontroller) to control the timed commutationsequence. This device commutated DC power from generic 12V DC powersupply to the motor windings to create four rotating magnetic poles onthe stator.

Motor assembly 100 described herein is similar to a universal motor. Theuniversal motor is so named because it is a type of electric motor thatcan operate on both AC and DC power. It is a commutated series-woundmotor where the stator's field coils are connected in series with therotor windings through a commutator. The universal motor is very similarto a DC series motor in construction, but is modified slightly to allowthe motor to operate properly on AC power. This type of electric motorcan operate well on AC because the current in both the field coils andthe armature (and the resultant magnetic fields) will alternate (reversepolarity) synchronously with the supply. Hence the resulting mechanicalforce will occur in a consistent direction of rotation, independent ofthe direction of applied voltage, but determined by the commutator andpolarity of the field coils.

FIG. 28A shows a three phase AC current with artificially predeterminedtwelve step segments potential points to match the timed commutationsequence shown in FIG. 28B (similar to FIG. 11C) for operation of an ACmotor (e.g., AC motor assembly 2900 illustrated in FIG. 29). The threesegments closed type stator segments have match potential as if it iscommutated with DC, however, now it is AC. This closed type winding canbe naturally driven by a three phase off grid utility alternatingcurrent (i.e., AC motors are self-commutating as its name stands foralternating current). However this closed type stator winding may beinterpreted as a DC commutated winding. It is inherently an AC motorstator winding while driven by a synchronized naturally self-commutatingAC. The AC may have a 120 degree phase angle offset. This closed typewinding is driven by self-commutating AC current does not need acommutator. The closed type stator winding is AC/DC or universalwinding.

FIG. 29 is a perspective view of an AC motor assembly 2900. The AC motorassembly 2900 features a stator 2910, rotor 2920 and coil windings 2912.An AC motor assembly would be manufactured and operated in the same waydescribed herein as DC motor assembly 100 with the same varying numberof slots. As discussed in connection with DC motor assembly 100, therotor 2920 can rotate inside the stator 2910 in response to statorrotating magnetic fields created by the coil windings 2912. Very similarin structure to the DC motor except the AC motor does not have acommutator but rather instead the speed of the AC motor assembly 2900 iscontrolled by a variable frequency driver 2940 (shown external to the ACmotor assembly 2900 but in alternative embodiments may be located insidethe AC motor assembly).

A generator assembly would be manufactured and operate in the same waydescribed herein as DC motor assembly 100 and AC motor assembly 2900.

As discussed, some of the benefits of the electric motors 100 and 2900disclosed herein with reference to FIGS. 1A-29 may include thefollowing. First, an electric motor that can operate at very highstarting torque because the coils are fully energized with DC current.This is generally comparable to the starting torque provided by a brushtype DC electric motor with permanent magnetic field, but without thedrawbacks of brushes inside the motor body. Second, an electrical motorwith a rotational speed that can be precisely controlled because therotation is progressed by timed commutation sequence steps. Such stepsare precisely controlled (for example by accurately timed electronicsand/or electronic processors) to a very high degree of accuracy. Third,an electric motor that operates at higher efficiency and power density.This is because the improved electrical motor stator can operate withoutbrush related contact loss and the winding is on the stator and easierto dissipate heat, thereby creating less heat and improving efficiency.Fourth, an electric motor capable of operating with AC current or DCcurrent with commutation. It is more capable of variable speeds athigher efficiencies than prior art AC motors powered by variablefrequency drives (VFD). This is because the motor avoids problems due tovarious VFD effects, such as higher frequency pulse width modulation(PWM) switching loss, AC skin effects, and motor total harmonicdistortion (THD) related core losses. Fifth, in some alternativeembodiments, where the stator and rotator can be viewed as having analmost infinite diameter meaning that there are no set limits on thenumber of slots, there is also provided an improved linear DC electricmotor as well. Sixth, in some alternative embodiments, when paired witha permanent magnetic rotor or squirrel cage rotor, there also may beprovided a regenerative motor, and act as a generator (based onFaraday's law of induction) when external power is applied to the rotor.Seventh, other embodiments described herein can also be applied in othertypes of electromechanical devices as well, such as rotating magneticbearings. Indeed any type of electromechanical device where AC rotatingmagnetic fields are used may potentially be improved according to themotors and methods described herein. Eighth, with up to four steps perslot count commutation resolution when commutated, the stator windingwith timed commutation sequence together create a step motor, the statorwinding. Ninth, with a commutator placed outside the motor body, the DCmotor can be built enclosed. Traditional DC motors can be replaced bythe motors disclosed herein with much reduced maintenance cost. Forexample, the commutator body can be easily replaced without ever openingthe motor body. Tenth, with end coil equally contributing to build thestator magnetic field, the motors disclosed herein are more energyefficient and have more power density. Tenth, with end coil equallycontribute to create stator magnetic field, this closed type statorwinding saves copper. Eleventh, the motors disclosed herein are DCmotors while commuted with the timed commutation sequence and have theadvantage of traditional DC brush motor high starting torque andprecision speed control of AC motor. Twelfth, the electric motors are ACmotors when powered by utility AC or off the shelf VFDs. Thirteenth, theelectric motors are stepper motors with four steps per slot. Fourteenth,the electric motor disclosed herein is a reluctant motor if fit with areluctant rotor (i.e., a reluctant motor is a type of electric motorthat induces non-permanent magnetic poles on a ferromagnetic rotor).Fifteenth, in the electric motors of this disclosure because currentfrom a collapsing magnetic field flows to low electric potential on theclosed type stator winding, there is no penalty for DC currentswitching. Sixteenth, the electric motor is a high power true brushlessDC, stepper and reluctant motor which can be built with the simplecontrol nature of DC current.

The motor embodiments described herein provide an improved high powerdensity, high torque traction motor. This motor may be suitable for roadand track vehicles, marine vessel, railways, trolleys, subways, andother applications where high torque, high power, and high efficiency isuseful. Such motors may also be used for automobiles, appliances,industrial automations, medical devices, power tools robotics or anyapplication that converts electric energy to kinetic energy.

The foregoing described embodiments have been presented for purposes ofillustration and description and are not intended to be exhaustive orlimiting in any sense. Alterations and modifications may be made to theembodiments disclosed herein without departing from the spirit and scopeof the invention. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention. The actual scope of the invention is to be defined by theclaims.

The definitions of the words or elements of the claims shall include notonly the combination of elements which are literally set forth, but allequivalent structure, material or acts for performing substantially thesame function in substantially the same way to obtain substantially thesame result.

The words used in this specification to describe the invention and itsvarious embodiments are to be understood not only in the sense of theircommonly defined meanings, but to include by special definition in thisspecification any structure, material or acts beyond the scope of thecommonly defined meanings. Thus if an element can be understood in thecontext of this specification as including more than one meaning, thenits use in a claim must be understood as being generic to all possiblemeanings supported by the specification and by the word itself.

Although process (or method) steps may be described or claimed in aparticular sequential order, such processes may be configured to work indifferent orders. In other words, any sequence or order of steps thatmay be explicitly described or claimed does not necessarily indicate arequirement that the steps be performed in that order unlessspecifically indicated. Further, some steps may be performedsimultaneously despite being described or implied as occurringnon-simultaneously (e.g., because one step is described after the otherstep) unless specifically indicated. Moreover, the illustration of aprocess by its depiction in a drawing does not imply that theillustrated process is exclusive of other variations and modificationsthereto, does not imply that the illustrated process or any of its stepsare necessary to the embodiment(s), and does not imply that theillustrated process is preferred. Where a process is described in anembodiment the process may operate without any user intervention.

Devices that are described as in “communication” with each other or“coupled” to each other need not be in continuous communication witheach other or in direct physical contact, unless expressly specifiedotherwise. On the contrary, such devices need only transmit to eachother as necessary or desirable, and may actually refrain fromexchanging data most of the time. For example, a machine incommunication with or coupled with another machine via the Internet maynot transmit data to the other machine for long period of time (e.g.weeks at a time). In addition, devices that are in communication with orcoupled with each other may communicate directly or indirectly throughone or more intermediaries.

Neither the Title (set forth at the beginning of the first page of thepresent application) nor the Abstract (set forth at the end of thepresent application) is to be taken as limiting in any way as the scopeof the disclosed invention(s). The title of the present application andheadings of sections provided in the present application are forconvenience only, and are not to be taken as limiting the disclosure inany way.

The invention claimed is:
 1. A method for commutating an electric motorcomprising: producing a stator rotating magnetic field from a closedtype winding of a stator including at least three coils coupled with arotor magnetically, the rotor capable of rotating when induced by thestator rotating magnetic field; controlling the stator rotating magneticfield with a commutator through a timed commutation sequence; whereinthe stator and the at least three coils are configured so that energyreleased from a collapsing stator rotating magnetic field on ade-energizing commutation step in a first of the at least three coils iscaptured by a second of the at least three coils energized on a nextstep of an energizing commutation step; wherein the timed commutationsequence is configured so that when a first commutation step iscommanded and the rotor is induced to a first detected position then asecond commutation step is commanded so that the rotor is induced to asecond detected position; and wherein the timed commutation sequence iscommutated to cause rotation of the stator rotating magnetic field sothat each phase of an electric potential is at least 150 electricdegrees positive and at least 150 electric degrees negative, wherein anelectric potential of a first phase has approximately 120 electricdegrees advance of a second phase and has approximately 240 electricdegrees advance of a third phase.
 2. The method of claim 1 wherein anenergizing commutation step is at both ends of the second of the atleast three coils which is commutated to more differential potential andchanges the current flow pattern in the closed type winding so as toadvance the stator rotating magnetic field by a commutation step in thetimed commutation sequence.
 3. The method of claim 1 wherein at thede-energizing commutation step, the current generated from part of acollapsing stator rotating magnetic field continuously flows in thedirection of a previous current direction to a lowest electric potentialinside the closed type stator winding until part of the collapsingstator rotating magnetic field is substantially collapsed and thecurrent generated from the part of the collapsing stator rotatingmagnetic field advance stator rotating magnetic field in a next step ofthe timed commutation sequence.
 4. The method of claim 1, wherein thestator rotating magnetic field advances at least one step at a time togenerate a time varying geometrically separated magnetic field accordingto the timed commutation sequence.
 5. The method of claim 1, wherein thetimed commutation sequence is a twelve step commutation sequence.
 6. Themethod of claim 1, wherein the electric motor can be used in any of thegroup consisting of: an electric motor, a railway engine, a trolleyengine, a subway engine, an electric vehicle motor, a vehicle'sauxiliary motor, an industrial automation control motor, an aviationvehicle, a marine vessel, a robotic machine, an automobile, anappliance, industrial automation equipment, a medical device, and apower tool.
 7. The method of claim 1, wherein the timed commutationsequence is a six step commutation sequence.
 8. The method of claim 1,wherein the commutator is Insulated Gate Bipolar Transistors (IGBT) ormetal-oxide-semiconductor field-effect transistors (MOSFET).
 9. Themethod of claim 1, wherein the commutator is a rotary mechanicalcommutator.
 10. A method for commutating an electric motor comprising:producing a stator rotating magnetic field from a closed type winding ofa stator including at least four coils coupled with a rotormagnetically, the rotor capable of rotating when induced by the statorrotating magnetic field; controlling the stator rotating magnetic fieldwith a commutator through a timed commutation sequence; wherein thestator and the at least four coils are configured so that energyreleased from a collapsing stator rotating magnetic field on ade-energizing commutation step in a first of the at least four coils iscaptured by a second of the at least four coils energized on a next stepof an energizing commutation step; wherein the timed commutationsequence is configured so that when a first commutation step iscommanded and the rotor is induced to a first detected position then asecond commutation step is commanded so that the rotor is induced to asecond position; and wherein the commutator is a plurality of switchescommutated to cause rotation of the stator rotating magnetic field sothat each phase of an electric potential is approximately 135 electricdegrees positive and approximately 135 electric degrees negative whereinan electric potential of a first phase has approximately 90 electricdegrees advance of a second phase and has approximately 180 electricdegrees advance of a third phase and approximately 270 degrees advanceof a fourth phase.
 11. The method of claim 10, wherein the commutator isone of the group consisting of Insulated Gate Bipolar Transistors (IGBT)or metal-oxide-semiconductor field-effect transistors (MOSFET).
 12. Themethod of claim 10, wherein the commutator is a rotary mechanicalcommutator.
 13. The method of claim 10, wherein an energizingcommutation step is at both ends of the second of the at least fourcoils which is commutated to more differential potential and changes thecurrent flow pattern in the closed type winding so as to advance thestator rotating magnetic field by a commutation step in the timedcommutation sequence.
 14. The method of claim 10, wherein at thede-energizing commutation step, the current generated from part of acollapsing stator rotating magnetic field continuously flows in thedirection of a previous current direction to a lowest electric potentialinside the closed type stator winding until part of the collapsingstator rotating magnetic field is substantially collapsed and thecurrent generated from the part of the collapsing stator rotatingmagnetic field advance stator rotating magnetic field in a next step ofthe timed commutation sequence.
 15. The method of claim 10, wherein thestator rotating magnetic field advances at least one step at a time togenerate a time varying geometrically separated magnetic field accordingto the timed commutation sequence.
 16. The method of claim 10, whereinthe timed commutation sequence is a sixteen step commutation sequence.17. The method of claim 10, wherein the timed commutation sequence is aeight step commutation sequence.
 18. The method of claim 10, wherein theelectric motor can be used in any of the group consisting of: anelectric motor, a railway engine, a trolley engine, a subway engine, anelectric vehicle motor, a vehicle's auxiliary motor, an industrialautomation control motor, an aviation vehicle, a marine vessel, arobotic machine, an automobile, an appliance, industrial automationequipment, a medical device, and a power tool.